As said, the non-electric RRC will fit with some help. the rear seats are a direct swap. However the front seats aren't! The width between the runners on anything other than a Discovery 1 (ie 200TDI, or 300TDI) will be considerably wider between the runners, this means that you need to make up a simple adaptor bracket to be able to mount the RRC seats.
You will see from the photo where the original disco seats bolted to the framework (screws showing) and also the holes were the RRC seats bolt to the additional bracket. I can confirm that's it's worth doing.